To recreate this all you need is to mod sync a save with mods that aren't yet compatible for 2.0

Yeah i wrote this horribly, let me rephrase it:

when you are using the sync mods feature for a save, if there is some mod that is not yet compatible with 2.0, during the game restart, the mod will simply just be disabled without letting the user know that the mod was disabled.

If a mod is required for a game save, for example you sync mods with a save file, and the mod has not been updated yet to be compatible with most recent Factorio update, the mod will be disabled but still pass syncing. The main issue is that the game doesn't tell you syncing was failed due to ...